Whanganui is expected to experience its coldest day of the year next Monday with a high of 10C forecast.
MetService meteorologist Mmathapelo Makgabutlane said the region recorded a high of 10.8C in July which was the coldest so far this year.
"People should prepare for a wet and windy day although the southerly winds are expected to ease later in the day," she said.
"In the meantime, Saturday will not be so bad with a high of 16C forecast although it will be showery."
Sunday will be cooler with a high of 14C with rain developing in the morning and heavy falls expected later in the day. Northwesterly winds are expected to give way to a strong southerly at night.